The present invention generally relates to a noise attenuation device and, more particularly, to an acoustic transducer device for noise attenuation.
Remarkable technological advances render the prevalence of various electronic products. Consumer electronic products, especially portable multi-media products, may provide real-time audio and video contents of interest. Most of the multi-media products are generally equipped with at least one speaker to give off sounds. However, since users may not clearly hear the sounds from speakers due to ambient noise, consequently, headphones or earphones, which may be capable of attenuating ambient noise, are widely used in conjunction with speakers for audio signal transmission.
A headphone may be designed to surround and cover the outer ears of a user to isolate ambient noise. For example, headphones may be devised to exert force against the ears so as to seal the ears tight and provide noise isolation. However, the pressure on the ears of a user may cause a phenomenon of autophony, which may make the user uneasy or uncomfortable. Furthermore, some headphones may have a large size and thus may cause inconvenience to their users.
Earphones are able to fit the auditory canals of ears so that ambient noise may be blocked outside. Moreover, a noise reduction circuit may be used in an earphone to compensate for noise at a low frequency range from approximately 16 Hertz (Hz) to 1 kilohertz (kHz). Nevertheless, such a noise reduction circuit may not process noise at a high frequency range over approximately 1 kHz. High-frequency noise, however, may also be sensed by the ears and interfere with audio signals of interest.
Therefore, it may be desirable to have an acoustic transducer device that is able to efficiently transmit audio signals and attenuate ambient noise.